What was found
ON DESCENT WITH WING ANTI-ICE ON, "R VALVE" LIGHT ILLUMINATED. WITH SWITCH IN THE OFF POSITION, LIGHT EXTINGUISHED. GROUNDED - YES. REF ASA DATA SUPPLEMENT, C/W B737-9 AMM 30-11-11-710-801. OPS TEST OF WING THERMAL ANTI-ICE VALVE. CYCLED MULTIPLE TIMES. ALL OSP TESTS PASSED. NO FURTHER ACTIONS REQUIRED.